High-toughness water-resistant dispersible concrete for TBM tunnel segment backfilling, and preparation method and application thereof

Abstract

The application discloses a kind of high-toughness water-resistant dispersible concrete for TBM tunnel segment back filling and its preparation method and application, belong to filling material technical field.The high-toughness water-resistant dispersible concrete provided by the application includes the following raw materials: ordinary portland cement, sulphoaluminate cement, fly ash, coal gangue powder, tailings powder, silica fume, construction waste recycled fine aggregate, coal gangue fine aggregate, slag, polypropylene fiber, basalt fiber, pure acrylic emulsion, styrene-acrylic emulsion, water reducing agent, polyethylene glycol, composite alkali activator, composite water-dispersible agent, water;Among them, the composite alkali activator includes water glass, sodium carbonate and biomass straw ash;Composite water-dispersible agent includes modified hydroxyethyl methyl cellulose ether, agar and xanthan gum.The application realizes the rapid setting of the material in water-rich stratum, the unity of excellent water-dispersible resistance, high toughness and high impermeability, and efficient resource utilization of various solid wastes through the above formula.

Description

Technical Field

[0001] This invention relates to the field of filling material technology, and in particular to a high-toughness, water-dispersible-resistant concrete for backfilling of TBM tunnel segments, its preparation method, and its application. Background Technology

[0002] Tunnel boring machine (TBM) construction technology is a key method for traversing complex geological conditions and constructing long-distance underground engineering projects. During TBM excavation, a ring-shaped gap forms between the outer wall of the precast tunnel segments and the outline of the excavated tunnel, which needs to be filled in a timely manner. This backfill layer is an important component for ensuring the stability of the tunnel structure, and its functions include restraining ground deformation, ensuring uniform stress on the tunnel lining segments, and improving the overall sealing and durability of the tunnel. Therefore, the backfilling of TBM tunnel segments places high demands on the performance of the backfill materials.

[0003] Currently, the commonly used backfilling method in engineering projects involves a two-step process: first, blowing in gravel, then injecting cement grout. However, this process has significant drawbacks: gravel blowing cannot guarantee complete compaction of the backfill gaps, easily leading to localized voids; during subsequent grouting, uneven diffusion of the grout within the gravel voids, coupled with increased grouting pressure, can cause segment misalignment, cracking, or even damage. These problems are particularly pronounced in water-rich strata—cement grout is easily diluted, washed away, and dispersed under high pressure or flowing water conditions, resulting in significant grout loss and further delaying the effective setting time. Ultimately, this leads to an insufficiently compacted backfill layer and inadequate strength development, resulting in uneven stress distribution, misalignment, cracking, and water leakage in the segment lining, significantly increasing operation and maintenance costs and safety risks.

[0004] To address the aforementioned shortcomings, recent studies have attempted to employ a method similar to synchronous grouting in tunnel boring machines (TBMs), directly pouring anti-dispersion concrete behind the tunnel segments to replace two separate processes with a single pour. However, existing anti-dispersion concrete still has limitations when applied to backfilling TBM segments: it generally lacks toughness, making it prone to brittle cracking under repeated loads or vibrations during operation; its impermeability is limited, making it difficult to effectively block groundwater seepage; and its scour resistance and construction fluidity in water-rich and flowing environments still have significant room for improvement. Furthermore, traditional materials rely heavily on cement and natural aggregates, resulting in a high environmental impact.

[0005] Therefore, in response to the backfilling requirements of TBM segments under water-rich strata, there is an urgent need to develop a backfilling concrete material that can quickly solidify, resist water erosion and dispersion, possess high toughness and excellent impermeability, and has good construction fluidity, so as to achieve one-time, dense and reliable filling of annular voids and ensure the long-term structural safety and waterproof performance of tunnel engineering. Summary of the Invention

[0006] In view of this, the present invention provides a high-toughness, water-dispersion-resistant concrete for backfilling behind TBM tunnel segments, its preparation method and application. The present invention achieves the unity of rapid setting and retention of backfill material in water-rich strata, excellent water dispersion resistance, high toughness and high impermeability by introducing a rapid-setting and early-strength composite cementitious system, a composite alkali-activated system, a composite anti-dispersion system and a physical-chemical dual toughening system, and realizes the efficient resource utilization of various industrial and construction solid wastes.

[0007] In a first aspect, the present invention provides a high-toughness, water-dispersible-resistant concrete for backfilling behind TBM tunnel segments, comprising, by weight: 210-270 parts of ordinary Portland cement, 80-120 parts of sulfoaluminate cement, 35-55 parts of fly ash, 20-40 parts of coal gangue powder, 30-50 parts of tailings powder, 25-35 parts of silica fume, and 60-100 parts of composite alkali activator. 360-440 parts of recycled fine aggregate from construction waste, 180-240 parts of fine aggregate from coal gangue, and 800-900 parts of slag; 6-8 parts polypropylene fiber, 5-10 parts basalt fiber, 25-45 parts pure acrylic emulsion, and 15-30 parts styrene-acrylic emulsion; 8-17 parts water-reducing agent, 6-9 parts polyethylene glycol, and 12-20 parts composite anti-water dispersible agent; 380-420 parts water; The composite alkali activator includes water glass, sodium carbonate, and biomass straw ash, with a mass ratio of water glass, sodium carbonate, and biomass straw ash of (2.0~3.0): (1.0~2.5): (2.5~4.5); the composite anti-water dispersibility agent includes modified hydroxyethyl methyl cellulose ether, agar, and xanthan gum, with a mass ratio of modified hydroxyethyl methyl cellulose ether, agar, and xanthan gum of (1.5~3.5): 1: (0.4~1.5).

[0008] Preferably, the modulus of the water glass is 2.0 to 2.8.

[0009] Preferably, the modified hydroxyethyl methyl cellulose ether is a hydroxyethyl methyl cellulose ether modified with formaldehyde.

[0010] Preferably, the molecular weight of the polyethylene glycol is 400-1000.

[0011] Preferably, the water-reducing agent includes an ether-based polycarboxylate water-reducing agent and an aliphatic water-reducing agent; the mass ratio of the ether-based polycarboxylate water-reducing agent to the aliphatic water-reducing agent is (1.0~2.0):1.

[0012] Preferably, the polypropylene fiber has an average length of 10-20 mm and a diameter of 30-50 μm; the basalt fiber has an average length of 12-18 mm and a diameter of 13-15 μm.

[0013] Preferably, the solid content of the pure acrylic emulsion is 45-55 wt%; the solid content of the styrene-acrylic emulsion is 45-55 wt%.

[0014] Preferably, the particle size of both the recycled construction waste fine aggregate and the coal gangue fine aggregate is no greater than 5 mm; the particle size of the slag is 5-15 mm; and the bulk density of the slag is 900-1100 kg / m³. 3 Water absorption rate ≤5wt%.

[0015] Preferably, the strength grade of the ordinary silicate cement is not lower than 42.5; the strength grade of the sulfoaluminate cement is not lower than 42.5.

[0016] Secondly, the present invention provides a method for preparing the above-mentioned high-toughness, water-dispersion-resistant concrete, comprising the following steps: Water glass, sodium carbonate, biomass straw ash and some water are premixed and stirred to form a composite alkali activator slurry; The composite anti-water dispersant was mixed with some water, heated to dissolve, and then cooled to obtain a gel-like precursor. The gel-like precursor, polyethylene glycol, water-reducing agent and remaining water are stirred and mixed, and then the composite alkali activator slurry is added and stirred to obtain a mixture. A dry mix is ​​prepared by mixing ordinary silicate cement, sulfoaluminate cement, fly ash, coal gangue powder, tailings powder, silica fume, recycled fine aggregate from construction waste, fine aggregate from coal gangue, slag, polypropylene fiber, and basalt fiber. The dry mix and the liquid mixture are stirred to obtain a concrete paste. Then, pure acrylic emulsion and styrene-acrylic emulsion are added and stirred evenly to obtain the high-toughness water-dispersible concrete.

[0017] Thirdly, the present invention provides the application of the above-mentioned high-toughness water-dispersible concrete or the high-toughness water-dispersible concrete prepared by the above-mentioned preparation method in the construction of void filling behind the segment wall of TBM tunnel engineering.

[0018] Compared with the prior art, the present invention has achieved the following beneficial effects: (1) This invention utilizes a binary composite cementitious system of ordinary silicate cement and sulfoaluminate cement, combined with a composite alkali activator composed of water glass, sodium carbonate, and biomass straw ash, to effectively synergistically activate the activity of solid waste admixtures such as fly ash and coal gangue powder. This system not only significantly accelerates the setting and hardening rate of the slurry, enabling it to quickly establish initial strength and resist water erosion in water-rich strata, but also optimizes the microstructure of the slurry through staged and continuous alkali activation, improving the later strength and durability of the material. This fundamentally solves the technical problems of traditional cement-based filling materials being easily diluted, dispersed, and slow-setting in dynamic water environments.

[0019] (2) This invention introduces a composite anti-dispersing agent composed of modified hydroxyethyl methyl cellulose ether, agar, and xanthan gum, which enables the material to possess both excellent static water anti-dispersion and dynamic water anti-erosion capabilities. Combined with the physical toughening effect of polypropylene fiber and basalt fiber, and the chemical film-forming and sealing effect of pure acrylic emulsion and styrene-acrylic emulsion, the prepared concrete exhibits high toughness, high crack resistance, and excellent impermeability after hardening, which can effectively inhibit misalignment, cracking, and water leakage of tunnel lining, and ensure the long-term safety and stability of the tunnel structure.

[0020] (3) This invention uses recycled fine aggregate from construction waste, fine aggregate from coal gangue, and slag as the main aggregates, making extensive use of industrial and construction solid waste. This solution not only realizes the large-scale and high-value synergistic utilization of various solid wastes in high-performance engineering materials, reducing dependence on natural sand and gravel resources, but also ensures good workability, volume stability, and final mechanical properties of concrete through optimized gradation design, achieving a balance between environmental protection and engineering economic benefits.

[0021] (4) The concrete prepared by this invention has a slump ≥176mm, a spread ≥565mm, an initial setting time of 3~4h, a dynamic water retention rate of ≥95% and ≥92% under the conditions of 0.5m / s flushing for 1h and 1m / s flushing for 30min, respectively, a 28d seepage pressure ≥0.8MPa, a 24h, 3d and 28d compressive strength greater than 4MPa, 7.5MPa and 20MPa, respectively, a 28d flexural-compression ratio ≥0.30, and a 28d water-land strength ratio ≥95%. Detailed Implementation

[0022] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0023] This invention provides a high-toughness, water-dispersible-resistant concrete for backfilling behind TBM tunnel segments, comprising the following raw materials in parts by weight: By weight, including: 210-270 parts of ordinary Portland cement, 80-120 parts of sulfoaluminate cement, 35-55 parts of fly ash, 20-40 parts of coal gangue powder, 30-50 parts of tailings powder, 25-35 parts of silica fume, and 60-100 parts of composite alkali activator. 360-440 parts of recycled fine aggregate from construction waste, 180-240 parts of fine aggregate from coal gangue, and 800-900 parts of slag; 6-8 parts polypropylene fiber, 5-10 parts basalt fiber, 25-45 parts pure acrylic emulsion, and 15-30 parts styrene-acrylic emulsion; 8-17 parts water-reducing agent, 6-9 parts polyethylene glycol, and 12-20 parts composite anti-water dispersible agent; 380-420 parts water; The composite alkali activator includes water glass, sodium carbonate, and biomass straw ash; the composite anti-water dispersibility agent includes modified hydroxyethyl methyl cellulose ether, agar, and xanthan gum.

[0024] The above-mentioned technical solution of the present invention constructs a high-performance filling material with multi-component and multi-system synergistic effect, which solves the multiple technical contradictions of traditional materials in water-rich strata, such as slow setting, easy dispersion, poor toughness, weak impermeability, and high environmental load.

[0025] In the design of the cementitious system, this invention employs a blend of ordinary Portland cement and sulfoaluminate cement. Ordinary Portland cement provides stable and reliable later-stage strength development, but its hydration is severely inhibited in both static and dynamic water environments. The introduction of sulfoaluminate cement leads to the rapid formation of its hydration product, ettringite, which significantly accelerates system setting and contributes to early strength, effectively resisting the scouring and dilution of the unset paste by water flow. Furthermore, the hydration processes of the two cements can influence and promote each other to a certain extent. The aluminum phase and sulfate ions released during the hydration of sulfoaluminate cement can accelerate the hydration of tricalcium silicate in ordinary Portland cement, while the calcium hydroxide produced during the hydration of ordinary Portland cement can provide an alkaline environment for the continuous hydration of sulfoaluminate cement. This interaction optimizes the setting and hardening curve of the system, achieving a balance between rapid setting, early strength, and long-term stability.

[0026] Mineral admixtures (fly ash, coal gangue powder, tailings powder, silica fume) and composite alkali activators (water glass, sodium carbonate, biomass straw ash) work synergistically to stimulate cementitious activity and optimize the slurry microstructure. The pozzolanic activity of fly ash and coal gangue powder, and the extremely high specific surface area and reactivity of silica fume, enable them to continuously consume calcium hydroxide produced during cement hydration under alkaline conditions, generating products such as hydrated calcium silicate (CSH) gel with cementitious properties. In particular, the composite alkali activator provides a multi-layered alkaline environment: water glass (sodium silicate) provides instantaneous high alkalinity, rapidly dissolving the glassy substance on the surface of the admixtures and initiating the pozzolanic reaction; sodium carbonate provides a continuous and mild alkaline environment, supporting the intermediate stage of the reaction; and biomass straw ash, as a solid alkali source, contains soluble potassium and sodium compounds and amorphous silicon, which can continuously release alkalinity and participate in the reaction in the later stages. This phased, multi-source alkali activation mode maximizes the potential gelling activity of solid waste admixtures, not only increasing the total amount and later strength of the gelling system, but also generating a large number of gel products that can effectively fill pores and refine the pore structure, which is the key to the material obtaining high impermeability.

[0027] The composite anti-dispersing agent (modified hydroxyethyl methyl cellulose ether, agar, xanthan gum) is specially designed for water-rich construction environments. The long molecular chains of the modified hydroxyethyl methyl cellulose ether bind to water via hydrogen bonds, significantly increasing the plastic viscosity of the slurry, effectively encapsulating and suspending solid particles, and inhibiting aggregate segregation and bleeding. Agar, upon heating and dissolving, forms a thermally reversible three-dimensional gel network upon cooling. In this invention, it is uniformly distributed in the slurry as gel particles. This gel particle network, with its excellent water absorption and retention capacity, physically locks in some of the mixing water, inhibiting bleeding and enhancing the overall integrity of the slurry during the plastic phase. The hydroxyl groups on its molecular chains can enrich calcium ions in the cement pore fluid, forming an ion-enriched layer on the surface of the gel particles. Through electrostatic interaction, this enhances the interaction between particles, effectively increasing the yield stress of the slurry and maintaining its integrity under hydrostatic pressure and low-shear dynamic water flow. Furthermore, the gel particles maintain structural integrity in the alkaline environment of the initial stage of cement hydration, providing scour protection for the slurry for several hours—a time window sufficient for grouting, setting, and early strength development. Xanthan gum exhibits typical pseudoplastic rheological behavior, with viscosity decreasing under high shear during pumping to facilitate application, and rapidly recovering upon settling, forming a complementary dynamic anti-erosion system with the agar network. This ternary synergistic system overcomes the technical limitation that increasing the dosage of traditional anti-water-dispersible materials inevitably leads to a significant decrease in fluidity, achieving high anti-erosion capability (1.0 m / s dynamic water retention rate ≥90%) while maintaining excellent application fluidity.

[0028] Polypropylene fibers, basalt fibers, pure acrylic emulsion, and styrene-acrylic emulsion together constitute a toughening and impermeability strengthening system. Polypropylene fibers have a low modulus and good ductility, effectively inhibiting the generation and development of microcracks during the plastic stage and early hardening stage of concrete. Basalt fibers have high modulus and high strength, and as micro-reinforcement, they can bear part of the load and limit crack propagation. The two form a physical reinforcement network at different scales, improving the toughness, crack resistance, and impact resistance of the material. This invention uses a compound system of pure acrylic emulsion and styrene-acrylic emulsion. Pure acrylic emulsion has high elasticity and good flexibility, while styrene-acrylic emulsion has strong adhesion and better alkali resistance. When used in combination, they can form a dual polymer network in hardened cement paste that has both high flexibility and strong adhesion, better bridging microcracks, absorbing fracture energy, and giving the material a more significant improvement in toughness and deformation capacity. When the material is under load, the polymer membrane dissipates energy through crack bridging, while the fibers further dissipate energy through pull-out effects. Their synergistic effect significantly inhibits crack propagation, achieving a 28-day refractory-to-compression ratio of ≥0.30, demonstrating excellent toughness. The polymer membrane simultaneously seals capillary channels and microcracks within the cement paste, reducing interconnected pores together with the fibers. This results in a final concrete impermeability pressure exceeding 0.8 MPa, while the 28-day compressive strength surpasses 20 MPa, showcasing the synergistic optimization of strength, toughness, and impermeability.

[0029] Finally, the aggregate system is mainly composed of recycled fine aggregate from construction waste, fine aggregate from coal gangue, and slag. This not only achieves large-scale resource utilization of solid waste and reduces environmental impact, but also optimizes material performance by utilizing their different characteristics. The recycled fine aggregate from construction waste has a rough surface and many edges, resulting in strong mechanical interlocking with the slurry; the relatively regular particles of coal gangue help improve the fluidity and pumpability of the mixture; and the slag, as coarse aggregate, is hard and forms a solid skeleton. Through reasonable gradation design and proportion control, this aggregate system can achieve good workability and volume stability while ensuring the mechanical properties of the materials. The addition of polyethylene glycol helps promote the dissolution and dispersion of components such as the composite anti-dispersibility agent, while the water-reducing agent is used to ensure the necessary fluidity and self-compacting properties of the slurry under low water-cement ratio conditions, ensuring dense filling.

[0030] In an optional embodiment of the present invention, the mass ratio of water glass, sodium carbonate, and biomass straw ash in the composite alkali activator is (2.0~3.0):(1.0~2.5):(2.5~4.5), more preferably (2.0~2.5):(1.5~2.5):(2.5~3.5). The water glass sodium silicate in the above-mentioned composite alkali activator of the present invention provides instantaneous high alkalinity (high concentration of OH-). -The rapid disruption of the glassy structure on the surface of admixtures such as fly ash and coal gangue powder by sodium carbonate (with silicate ions) initiates the pozzolanic reaction, which is crucial for early strength development. Sodium carbonate, with its moderate alkalinity and slow dissolution and reaction rates, provides a continuous and stable alkaline environment, preventing a sudden drop in pH and supporting sustained strength growth. Biomass straw ash not only serves as a solid alkali source (rich in K₂O, Na₂O, etc.), providing a persistent weakly alkaline microenvironment after dissolution, but also contains amorphous SiO₂, which continuously participates in the pozzolanic reaction, further optimizing the gel phase composition and microstructure. The above compounding ratio ensures a balance between the strength, persistence, and structure of the reaction products induced by alkalinity.

[0031] In an optional embodiment of the present invention, the modulus of the water glass is 2.0 to 2.8, more preferably 2.2 to 2.6. If the modulus is too low, the alkalinity will be too strong, which may lead to excessively rapid solidification, severe loss of fluidity, and easy cracking; if the modulus is too high, the viscosity will be too high, the solubility will decrease, which is not conducive to construction and reduces the activation efficiency.

[0032] This invention does not impose special restrictions on the biomass straw ash, such as corn, sunflower, rice, wheat, and other crop straw ash, with a K2O content of not less than 15wt%, a SiO2 content of not less than 18wt%, a CaO content of not less than 12wt%, and a loss on ignition of not more than 15wt%. This invention does not impose special restrictions on its preparation method; for example, corn straw can be calcined at a controlled temperature of 600-800℃ for 1-2 hours, followed by grinding to a specific surface area of ​​not less than 400 m². 2 / kg.

[0033] In an optional embodiment of the present invention, the mass ratio of modified hydroxyethyl methyl cellulose ether, agar, and xanthan gum in the composite anti-dispersibility agent is (1.5~3.5):1:(0.4~1.5). The modified hydroxyethyl methyl cellulose ether is a hydroxyethyl methyl cellulose ether modified with formaldehyde. After formaldehyde modification, some hydroxyl groups on the molecular chain of the hydroxyethyl methyl cellulose ether are protected or cross-linked, significantly improving its solubility uniformity and anti-agglomeration ability in strong electrolytes and high-alkalinity cement pastes. It can provide long-lasting thickening and lock in free water through hydrogen bonding and hydration. The three-dimensional rigid gel network of agar can physically coat and fix cement particles, providing a static anti-dispersibility skeletal support. Xanthan gum imparts strong pseudoplasticity (shear-thinning properties) to the paste, ensuring that the viscosity decreases under pumping shear for easy application, and the viscosity recovers rapidly after pumping stops, resisting erosion by flowing water.

[0034] This invention does not impose any particular limitation on the preparation method of modified hydroxyethyl methyl cellulose ether. A preferred method is as follows: 100 parts by weight of hydroxyethyl methyl cellulose ether is dispersed in a mixed solvent of ethanol and water. 3-8 parts by weight of formaldehyde solution are added under stirring. The pH is adjusted to 2-4 with acid, and the reaction is carried out at 50-70°C for 2-4 hours. After the reaction is complete, the mixture is neutralized with alkali, and after washing, drying, and pulverizing, the modified product is obtained. The formaldehyde solution is preferably a 30-40 wt% formaldehyde solution.

[0035] In an optional embodiment of the present invention, the molecular weight of the polyethylene glycol is 400-1000, more preferably 400-800, which provides both good water solubility and dispersibility. Polyethylene glycol (PEG) is mainly used as a nonionic surfactant and dispersant to improve the solubility and dispersion of other additives (especially composite anti-water dispersants) in water, and also has certain air-entraining and retarding effects.

[0036] In an optional embodiment of the present invention, the water-reducing agent comprises an ether-based polycarboxylate superplasticizer and an aliphatic superplasticizer; the mass ratio of the ether-based polycarboxylate superplasticizer to the aliphatic superplasticizer is (1.0~2.0):1. The ether-based polycarboxylate superplasticizer mainly disperses particles through steric hindrance, maintaining good molecular structural stability even in strongly alkaline environments, providing long-term flowability retention. The aliphatic superplasticizer mainly functions through electrostatic repulsion, exhibiting rapid adsorption and significantly improving the initial flowability of the slurry. In this invention, the ether-based polycarboxylate superplasticizer has a water reduction rate of not less than 40% and an effective ingredient content ≥96wt%. The aliphatic superplasticizer has a water reduction rate of not less than 20% and an effective ingredient content ≥94wt%.

[0037] In an optional embodiment of the present invention, the polypropylene fiber has an average length of 10-20 mm and a diameter of 30-50 μm; the basalt fiber has an average length of 12-18 mm and a diameter of 13-15 μm.

[0038] In an optional embodiment of the present invention, the solid content of the pure acrylic emulsion is 45-55 wt%; the solid content of the styrene-acrylic emulsion is 45-55 wt%. The film-forming material of the pure acrylic emulsion is an acrylate copolymer, which has flexible film formation and good weather resistance; the film-forming material of the styrene-acrylic emulsion is a copolymer of styrene and acrylate, which has higher film hardness and stronger adhesion due to the introduction of rigid styrene segments. Both the pure acrylic emulsion and the styrene-acrylic emulsion can demulsify during cement hydration, forming an interpenetrating polymer network film at pores and microcracks, significantly improving the toughness, deformation capacity, and impermeability of the material.

[0039] In an optional embodiment of the present invention, the particle size of both the recycled construction waste fine aggregate and the coal gangue fine aggregate is no greater than 5 mm. The water absorption rate of the recycled construction waste fine aggregate is ≤8 wt%, and the content of micro-powder particles with a particle size of less than 75 μm is ≤5 wt%. The water absorption rate of the coal gangue fine aggregate is ≤8 wt%, the sulfide content is ≤1 wt%, and the content of micro-powder particles with a particle size of less than 75 μm is ≤3 wt%.

[0040] In an optional embodiment of the present invention, the particle size of the slag is 5-15 mm; the bulk density of the slag is 900-1100 kg / m³. 3 Water absorption rate ≤5wt%, sulfide and sulfate content ≤2.0wt%.

[0041] In an optional embodiment of the present invention, the ordinary silicate cement has a strength grade of not less than 42.5 and an average particle size of not more than 40 μm. The sulfoaluminate cement has a strength grade of not less than 42.5 and a specific surface area ≥ 400 m². 2 / kg.

[0042] In an optional embodiment of the present invention, the specific surface area of ​​the silica fume is ≥15000 m². 2 / kg, SiO2 content ≥85wt%.

[0043] In an optional embodiment of the present invention, the specific surface area of ​​the fly ash, coal gangue powder, and tailings powder is 400~600m². 2 / kg.

[0044] The present invention also provides a method for preparing the above-mentioned high-toughness, water-dispersion-resistant concrete, comprising the following steps: Water glass, sodium carbonate, biomass straw ash, and a portion of water are premixed and stirred to form a composite alkali activator slurry; the water used in this step is preferably 10-15% of the total water volume. The composite anti-water dispersible agent is mixed with a portion of water and heated to dissolve, then cooled to obtain a gel-like precursor; the heating temperature is 85~95℃, and the temperature is cooled to below 35℃; the water volume in this step is preferably 20~30% of the total water volume; in the composite anti-water dispersible agent, the agar and xanthan gum are used in the form of 80~100 mesh powder; The gel-like precursor, polyethylene glycol, water-reducing agent, and remaining water are stirred and mixed. At this time, the gel network is temporarily broken under shear, and the system becomes a uniform viscous liquid. Then, the composite alkali activator slurry is added and stirred to obtain a mixture. The composite alkali activator slurry is added last to reduce the potential impact of its strong alkaline environment on the performance of organic components such as water-reducing agent, and to ensure the stability of the workability of the mixture. A dry mix is ​​prepared by mixing ordinary silicate cement, sulfoaluminate cement, fly ash, coal gangue powder, tailings powder, silica fume, recycled fine aggregate from construction waste, fine aggregate from coal gangue, slag, polypropylene fiber, and basalt fiber. The dry mix and the liquid mixture are stirred to obtain a concrete paste. Then, pure acrylic emulsion and styrene-acrylic emulsion are added and stirred evenly to obtain the high-toughness water-dispersible concrete.

[0045] This invention also provides the application of the aforementioned high-toughness, water-dispersible concrete in the filling of voids behind the tunnel lining segments in TBM tunnel engineering. The aforementioned high-toughness, water-dispersible concrete can be pumped and injected using a concrete pump.

[0046] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0047] In the following examples, the modified hydroxyethyl methyl cellulose ether was prepared as follows: 100 parts by weight of hydroxyethyl methyl cellulose ether were weighed and placed in a reactor. A mixed solvent consisting of 250 parts by weight of anhydrous ethanol and 150 parts by weight of deionized water was added. Stirring was started, and the mixture was allowed to fully disperse and swell at 300 rpm for 30 minutes. While stirring continuously, 5 parts by weight of formaldehyde solution (concentration 37 wt%) was slowly added dropwise to the system. After the addition was complete, the pH of the reaction system was adjusted to 2.5 with dilute hydrochloric acid. The temperature of the reaction system was raised to 60°C and maintained at this temperature for 3 hours. After the reaction was completed, the system was cooled to room temperature. The pH of the reaction system was neutralized to 7.0 with 10 wt% sodium hydroxide solution. The obtained product was filtered, and the filter cake was washed three times with 300 parts by weight of 70% ethanol aqueous solution to remove residual reaction reagents and byproducts. The washed filter cake was dried in a vacuum drying oven at 80°C for 6 hours until constant weight was achieved. Finally, the dried block product was pulverized using a pulverizer and passed through a 100-mesh sieve to obtain a white powdery modified hydroxyethyl methyl cellulose ether product.

[0048] In the following examples, the ordinary Portland cement has a strength grade of PO 42.5 and an average particle size of approximately 35 μm. The sulfoaluminate cement has a strength grade of R.SAC 42.5 and a specific surface area of ​​approximately 450 m². 2 / kg. The specific surface area of ​​fly ash, coal gangue powder, and tailings powder is approximately 450 m². 2 / kg. The specific surface area of ​​silica fume is approximately 18,000 m². 2 / kg, SiO2 content is 92wt%. The particle size of recycled construction waste fine aggregate is no greater than 5mm, water absorption rate is 6wt%, and the content of micro-particles with a particle size less than 75μm is 4wt%. The particle size of coal gangue fine aggregate is no greater than 5mm, water absorption rate is 5wt%, sulfide content is 0.5wt%, and the content of micro-particles with a particle size less than 75μm is 2wt%. The particle size of slag is 5-15mm, and the bulk density is 1050 kg / m³. 3 The water absorption rate is 3wt%, and the sulfide and sulfate content is 1.5wt%. The average length of the polypropylene fiber is 15mm and the diameter is 40μm. The average length of the basalt fiber is 12mm and the diameter is 14μm. The pure acrylic emulsion is an acrylate copolymer emulsion with a solid content of 50wt%. The styrene-acrylic emulsion is a styrene-butyl acrylate copolymer emulsion with a solid content of 50wt%. The water reduction rate of the ether-based polycarboxylate superplasticizer is 42%, and the effective ingredient content is ≥96wt%. The water reduction rate of the aliphatic superplasticizer is 22%, and the effective ingredient content is ≥94wt%. The molecular weight of the polyethylene glycol (PEG600) is 600. The corn stalk ash is obtained by calcining corn stalks at 700℃ for 1.5 hours, followed by grinding to a specific surface area of ​​450 m². 2 The sample was prepared at a concentration of 17.2 wt% K2O, 21.5 wt% SiO2, 14.3 wt% CaO, and 13.7 wt% loss on ignition.

[0049] Example 1 This embodiment provides a method for preparing high-toughness, water-dispersible concrete.

[0050] The formulation (parts by weight) of this embodiment is as follows: 210 parts ordinary silicate cement, 120 parts sulfoaluminate cement, 55 parts fly ash, 30 parts coal gangue powder, 50 parts tailings powder, 25 parts silica fume, 400 parts recycled fine aggregate from construction waste, 240 parts fine aggregate from coal gangue, 850 parts slag, 8 parts polypropylene fiber, 5 parts basalt fiber, 25 parts pure acrylic emulsion, 30 parts styrene-acrylic emulsion, 7.5 parts ether-based polycarboxylate superplasticizer, 5 parts aliphatic superplasticizer, 9 parts polyethylene glycol (PEG600), 70 parts composite alkali activator, 16 parts composite anti-water dispersibility agent, and 420 parts water. The composite alkali activator is composed of water glass, sodium carbonate, and corn stalk ash in a mass ratio of 2:2.5:2.5, with a water glass modulus of 2.4. The composite anti-water dispersant is composed of modified hydroxyethyl methyl cellulose ether, agar, and xanthan gum in a mass ratio of 2:1:1.

[0051] Preparation method: (1) Preparation of composite alkali activator slurry: Take 55 parts of water, mix with water glass, sodium carbonate and corn straw ash, stir at 300 rpm for 5 minutes to form a uniform slurry for later use.

[0052] (2) Preparation of composite anti-water dispersant gel precursor: Take 115 parts of water, add modified hydroxyethyl methyl cellulose ether, agar, and xanthan gum, heat to 90°C and keep stirring until completely dissolved to form a homogeneous solution. Stop heating, continue stirring and cool to below 35°C to obtain a gel precursor.

[0053] (3) Preparation of the mixture: Mix the gel precursor obtained in step (2), polyethylene glycol, ether polycarboxylate superplasticizer, aliphatic superplasticizer and the remaining water (250 parts), and stir at 500 rpm for 3 minutes until uniform. Then, add the composite alkali activator slurry from step (1) while stirring, and stir at 300 rpm for 2 minutes to obtain the mixture.

[0054] (4) Preparation of dry mix: Put ordinary silicate cement, sulfoaluminate cement, fly ash, coal gangue powder, tailings powder, silica fume, recycled fine aggregate from construction waste, coal gangue fine aggregate, slag, polypropylene fiber, and basalt fiber into a mixer and dry mix at 150 rpm for 5 minutes until evenly mixed.

[0055] (5) Mixing and modification: The dry mix from step (4) and the liquid mixture from step (3) are mixed. First, the mixture is stirred at 600 rpm for 1.5 minutes, and then at 300 rpm for 2 minutes to form a uniform concrete paste. Finally, pure acrylic emulsion and styrene-acrylic emulsion are added, and the mixture is stirred at 400 rpm for 4 minutes to obtain the high-toughness water-dispersible concrete.

[0056] Example 2 This embodiment provides a method for preparing high-toughness, water-dispersible concrete.

[0057] The formulation (parts by weight) of this embodiment is as follows: 240 parts ordinary silicate cement, 80 parts sulfoaluminate cement, 55 parts fly ash, 20 parts coal gangue powder, 50 parts tailings powder, 35 parts silica fume, 440 parts recycled fine aggregate from construction waste, 180 parts fine aggregate from coal gangue, 800 parts slag, 6 parts polypropylene fiber, 7.5 parts basalt fiber, 45 parts pure acrylic emulsion, 15 parts styrene-acrylic emulsion, 10 parts ether-based polycarboxylate superplasticizer, 3 parts aliphatic superplasticizer, 7.5 parts polyethylene glycol (PEG600), 80 parts composite alkali activator, 16 parts composite anti-water dispersibility agent, and 380 parts water. The composite alkali activator is composed of water glass, sodium carbonate, and corn stalk ash in a mass ratio of 2.5:2:3.5, with a water glass modulus of 2.4. The composite anti-water dispersant is composed of modified hydroxyethyl methyl cellulose ether, agar, and xanthan gum in a mass ratio of 5:2:1.

[0058] Preparation method: (1) Preparation of composite alkali activator slurry: Take 55 parts of water, mix with water glass, sodium carbonate and corn straw ash, stir at 300 rpm for 5 minutes to form a uniform slurry for later use.

[0059] (2) Preparation of composite anti-water dispersant gel precursor: Take 115 parts of water, add modified hydroxyethyl methyl cellulose ether, agar, and xanthan gum, heat to 90°C and keep stirring until completely dissolved to form a homogeneous solution. Stop heating, continue stirring and cool to below 35°C to obtain a gel precursor.

[0060] (3) Preparation of the mixture: Mix the gel precursor obtained in step (2), polyethylene glycol, ether polycarboxylate superplasticizer, aliphatic superplasticizer and the remaining water (210 parts), and stir at 500 rpm for 3 minutes until uniform. Then, add the composite alkali activator slurry from step (1) while stirring, and stir at 300 rpm for 2 minutes to obtain the mixture.

[0061] (4) Preparation of dry mix: Put ordinary silicate cement, sulfoaluminate cement, fly ash, coal gangue powder, tailings powder, silica fume, recycled fine aggregate from construction waste, coal gangue fine aggregate, slag, polypropylene fiber, and basalt fiber into a mixer and dry mix at 150 rpm for 5 minutes until evenly mixed.

[0062] (5) Mixing and modification: The dry mix from step (4) and the liquid mixture from step (3) are mixed. First, the mixture is stirred at 600 rpm for 1.5 minutes, and then at 300 rpm for 2 minutes to form a uniform concrete paste. Finally, pure acrylic emulsion and styrene-acrylic emulsion are added, and the mixture is stirred at 400 rpm for 4 minutes to obtain the high-toughness water-dispersible concrete.

[0063] Example 3 This embodiment provides a method for preparing high-toughness, water-dispersible concrete.

[0064] The formulation (parts by weight) of this embodiment is as follows: 210 parts ordinary silicate cement, 100 parts sulfoaluminate cement, 45 parts fly ash, 40 parts coal gangue powder, 40 parts tailings powder, 35 parts silica fume, 440 parts recycled fine aggregate from construction waste, 210 parts fine aggregate from coal gangue, 850 parts slag, 7 parts polypropylene fiber, 7.5 parts basalt fiber, 35 parts pure acrylic emulsion, 15 parts styrene-acrylic emulsion, 10 parts ether-based polycarboxylate superplasticizer, 3 parts aliphatic superplasticizer, 7.5 parts polyethylene glycol (PEG600), 85 parts composite alkali activator, 14 parts composite anti-water dispersible agent, and 400 parts water. The composite alkali activator is composed of water glass, sodium carbonate, and corn stalk ash in a mass ratio of 3:1:4.5, with a water glass modulus of 2.4. The composite anti-water dispersant is composed of modified hydroxyethyl methyl cellulose ether, agar, and xanthan gum in a mass ratio of 6:5:3.

[0065] Preparation method: (1) Preparation of composite alkali activator slurry: Take 60 parts of water, mix with water glass, sodium carbonate and corn straw ash, stir at 300 rpm for 5 minutes to form a uniform slurry for later use.

[0066] (2) Preparation of composite anti-water dispersant gel precursor: Take 110 parts of water, add modified hydroxyethyl methyl cellulose ether, agar, and xanthan gum, heat to 90°C and keep stirring until completely dissolved to form a homogeneous solution. Stop heating, continue stirring and cool to below 35°C to obtain a gel precursor.

[0067] (3) Preparation of the mixture: Mix the gel precursor obtained in step (2), polyethylene glycol, ether polycarboxylate superplasticizer, aliphatic superplasticizer and the remaining water (230 parts), and stir at 500 rpm for 3 minutes until uniform. Then, add the composite alkali activator slurry from step (1) while stirring, and stir at 300 rpm for 2 minutes to obtain the mixture.

[0068] (4) Preparation of dry mix: Put ordinary silicate cement, sulfoaluminate cement, fly ash, coal gangue powder, tailings powder, silica fume, recycled fine aggregate from construction waste, coal gangue fine aggregate, slag, polypropylene fiber, and basalt fiber into a mixer and dry mix at 150 rpm for 5 minutes until evenly mixed.

[0069] (5) Mixing and modification: The dry mix from step (4) and the liquid mixture from step (3) are mixed. First, the mixture is stirred at 600 rpm for 1.5 minutes, and then at 300 rpm for 2 minutes to form a uniform concrete paste. Finally, pure acrylic emulsion and styrene-acrylic emulsion are added, and the mixture is stirred at 400 rpm for 4 minutes to obtain the high-toughness water-dispersible concrete.

[0070] Example 4 This embodiment provides a method for preparing high-toughness, water-dispersible concrete.

[0071] The formulation (parts by weight) of this embodiment is as follows: 270 parts ordinary silicate cement, 100 parts sulfoaluminate cement, 35 parts fly ash, 30 parts coal gangue powder, 30 parts tailings powder, 30 parts silica fume, 360 parts recycled fine aggregate from construction waste, 210 parts fine aggregate from coal gangue, 900 parts slag, 8 parts polypropylene fiber, 10 parts basalt fiber, 25 parts pure acrylic emulsion, 22.5 parts styrene-acrylic emulsion, 5 parts ether-based polycarboxylate superplasticizer, 5 parts aliphatic superplasticizer, 6 parts polyethylene glycol (PEG600), 70 parts composite alkali activator, 13 parts composite anti-water dispersibility agent, and 420 parts water. The composite alkali activator is composed of water glass, sodium carbonate, and corn stalk ash in a mass ratio of 3:1.5:2.5, with a water glass modulus of 2.4. The composite anti-water dispersant is composed of modified hydroxyethyl methyl cellulose ether, agar, and xanthan gum in a mass ratio of 6:3:4.

[0072] Preparation method: (1) Preparation of composite alkali activator slurry: Take 55 parts of water, mix with water glass, sodium carbonate and corn straw ash, stir at 300 rpm for 5 minutes to form a uniform slurry for later use.

[0073] (2) Preparation of composite anti-water dispersant gel precursor: Take 115 parts of water, add modified hydroxyethyl methyl cellulose ether, agar, and xanthan gum, heat to 90°C and keep stirring until completely dissolved to form a homogeneous solution. Stop heating, continue stirring and cool to below 35°C to obtain a gel precursor.

[0074] (3) Preparation of the mixture: Mix the gel precursor obtained in step (2), polyethylene glycol, ether polycarboxylate superplasticizer, aliphatic superplasticizer and the remaining water (250 parts), and stir at 500 rpm for 3 minutes until uniform. Then, add the composite alkali activator slurry from step (1) while stirring, and stir at 300 rpm for 2 minutes to obtain the mixture.

[0075] (4) Preparation of dry mix: Put ordinary silicate cement, sulfoaluminate cement, fly ash, coal gangue powder, tailings powder, silica fume, recycled fine aggregate from construction waste, coal gangue fine aggregate, slag, polypropylene fiber, and basalt fiber into a mixer and dry mix at 150 rpm for 5 minutes until evenly mixed.

[0076] (5) Mixing and modification: The dry mix from step (4) and the liquid mixture from step (3) are mixed. First, the mixture is stirred at 600 rpm for 1.5 minutes, and then at 300 rpm for 2 minutes to form a uniform concrete paste. Finally, pure acrylic emulsion and styrene-acrylic emulsion are added, and the mixture is stirred at 400 rpm for 4 minutes to obtain the high-toughness water-dispersible concrete.

[0077] Example 5 This embodiment provides a method for preparing high-toughness, water-dispersible concrete.

[0078] The formulation (parts by weight) of this embodiment is as follows: 270 parts ordinary silicate cement, 80 parts sulfoaluminate cement, 45 parts fly ash, 20 parts coal gangue powder, 40 parts tailings powder, 30 parts silica fume, 400 parts recycled fine aggregate from construction waste, 180 parts fine aggregate from coal gangue, 900 parts slag, 6 parts polypropylene fiber, 10 parts basalt fiber, 45 parts pure acrylic emulsion, 30 parts styrene-acrylic emulsion, 7.5 parts ether-based polycarboxylate superplasticizer, 7 parts aliphatic superplasticizer, 9 parts polyethylene glycol (PEG600), 85 parts composite alkali activator, 16 parts composite anti-water dispersibility agent, and 400 parts water. The composite alkali activator is composed of water glass, sodium carbonate, and corn stalk ash in a mass ratio of 2.5:1.5:4.5, with a water glass modulus of 2.4. The composite anti-water dispersant is composed of modified hydroxyethyl methyl cellulose ether, agar, and xanthan gum in a mass ratio of 10:3:3.

[0079] Preparation method: (1) Preparation of composite alkali activator slurry: Take 60 parts of water, mix with water glass, sodium carbonate and corn straw ash, stir at 300 rpm for 5 minutes to form a uniform slurry for later use.

[0080] (2) Preparation of composite anti-water dispersant gel precursor: Take 115 parts of water, add modified hydroxyethyl methyl cellulose ether, agar, and xanthan gum, heat to 90°C and keep stirring until completely dissolved to form a homogeneous solution. Stop heating, continue stirring and cool to below 35°C to obtain a gel precursor.

[0081] (3) Preparation of the mixture: Mix the gel precursor obtained in step (2), polyethylene glycol, ether polycarboxylate superplasticizer, aliphatic superplasticizer and the remaining water (225 parts), and stir at 500 rpm for 3 minutes until uniform. Then, add the composite alkali activator slurry from step (1) while stirring, and stir at 300 rpm for 2 minutes to obtain the mixture.

[0082] (4) Preparation of dry mix: Put ordinary silicate cement, sulfoaluminate cement, fly ash, coal gangue powder, tailings powder, silica fume, recycled fine aggregate from construction waste, coal gangue fine aggregate, slag, polypropylene fiber, and basalt fiber into a mixer and dry mix at 150 rpm for 5 minutes until evenly mixed.

[0083] (5) Mixing and modification: The dry mix from step (4) and the liquid mixture from step (3) are mixed. First, the mixture is stirred at 600 rpm for 1.5 minutes, and then at 300 rpm for 2 minutes to form a uniform concrete paste. Finally, pure acrylic emulsion and styrene-acrylic emulsion are added, and the mixture is stirred at 400 rpm for 4 minutes to obtain the high-toughness water-dispersible concrete.

[0084] Example 6 This embodiment provides a method for preparing high-toughness, water-dispersible concrete.

[0085] The formulation (parts by weight) of this embodiment is as follows: 240 parts ordinary silicate cement, 120 parts sulfoaluminate cement, 35 parts fly ash, 40 parts coal gangue powder, 30 parts tailings powder, 25 parts silica fume, 360 parts recycled fine aggregate from construction waste, 240 parts fine aggregate from coal gangue, 800 parts slag, 7 parts polypropylene fiber, 5 parts basalt fiber, 35 parts pure acrylic emulsion, 22.5 parts styrene-acrylic emulsion, 5 parts ether-based polycarboxylate superplasticizer, 7 parts aliphatic superplasticizer, 6 parts polyethylene glycol (PEG600), 80 parts composite alkali activator, 15 parts composite anti-water dispersibility agent, and 380 parts water. The composite alkali activator is composed of water glass, sodium carbonate, and corn stalk ash in a mass ratio of 2:2.5:3.5, with a water glass modulus of 2.4. The composite anti-water dispersant is composed of modified hydroxyethyl methyl cellulose ether, agar, and xanthan gum in a mass ratio of 8:5:2.

[0086] Preparation method: (1) Preparation of composite alkali activator slurry: Take 60 parts of water, mix with water glass, sodium carbonate and corn straw ash, stir at 300 rpm for 5 minutes to form a uniform slurry for later use.

[0087] (2) Preparation of composite anti-water dispersant gel precursor: Take 115 parts of water, add modified hydroxyethyl methyl cellulose ether, agar, and xanthan gum, heat to 90°C and keep stirring until completely dissolved to form a homogeneous solution. Stop heating, continue stirring and cool to below 35°C to obtain a gel precursor.

[0088] (3) Preparation of the mixture: Mix the gel precursor obtained in step (2), polyethylene glycol, ether polycarboxylate superplasticizer, aliphatic superplasticizer and the remaining water (205 parts), and stir at 500 rpm for 3 minutes until uniform. Then, add the composite alkali activator slurry from step (1) while stirring, and stir at 300 rpm for 2 minutes to obtain the mixture.

[0089] (4) Preparation of dry mix: Put ordinary silicate cement, sulfoaluminate cement, fly ash, coal gangue powder, tailings powder, silica fume, recycled fine aggregate from construction waste, coal gangue fine aggregate, slag, polypropylene fiber, and basalt fiber into a mixer and dry mix at 150 rpm for 5 minutes until evenly mixed.

[0090] (5) Mixing and modification: The dry mix from step (4) and the liquid mixture from step (3) are mixed. First, the mixture is stirred at 600 rpm for 1.5 minutes, and then at 300 rpm for 2 minutes to form a uniform concrete paste. Finally, pure acrylic emulsion and styrene-acrylic emulsion are added, and the mixture is stirred at 400 rpm for 4 minutes to obtain the high-toughness water-dispersible concrete.

[0091] Comparative Example 1 The difference between this comparative example and Example 5 is that no sulfoaluminate cement was added in this comparative example, and the missing part was replaced by an equal amount of ordinary silicate cement.

[0092] Comparative Example 2 The difference between this comparative example and Example 5 is that this comparative example did not contain a composite alkali activator (i.e., it does not contain water glass, sodium carbonate, or corn stalk ash).

[0093] Comparative Example 3 The difference between this comparative example and Example 5 is that this comparative example did not contain a composite anti-water dispersant (i.e., it does not contain modified hydroxyethyl methyl cellulose ether, agar, or xanthan gum).

[0094] Comparative Example 4 The difference between this comparative example and Example 5 is that this comparative example did not include polypropylene fiber, basalt fiber, pure acrylic emulsion, and styrene-acrylic emulsion.

[0095] Comparative Example 5 The difference between this comparative example and Example 5 is that this comparative example uses an equal amount of modified hydroxyethyl methyl cellulose ether to replace the composite anti-water dispersant.

[0096] Comparative Example 6 The difference between this comparative example and Example 5 is that this comparative example uses an equal amount of xanthan gum to replace the composite anti-water dispersant.

[0097] Comparative Example 7 The difference between this comparative example and Example 5 is that this comparative example uses an equal amount of agar to replace the composite anti-water dispersant.

[0098] Comparative Example 8 The difference between this comparative example and Example 5 is that the agar component in the composite anti-dispersibility agent is replaced with an equal amount of sodium carboxymethyl cellulose. That is, the composite anti-dispersibility agent is composed of modified hydroxyethyl methyl cellulose ether, sodium carboxymethyl cellulose, and xanthan gum in a mass ratio of 10:3:3, and the total amount of the composite anti-dispersibility agent added is still 16 parts.

[0099] Comparative Example 9 The difference between this comparative example and Example 5 lies in the preparation method. The preparation method of this comparative example is as follows: (1) Mix water glass, sodium carbonate, modified hydroxyethyl methyl cellulose ether, agar, xanthan gum, polyethylene glycol, ether-based polycarboxylate superplasticizer, aliphatic superplasticizer and water, and stir at 300 rpm for 20 minutes to obtain a mixture.

[0100] (2) Preparation of dry mix: Put ordinary silicate cement, sulfoaluminate cement, fly ash, coal gangue powder, tailings powder, silica fume, recycled fine aggregate from construction waste, coal gangue fine aggregate, slag, polypropylene fiber, basalt fiber, and corn stalk ash into a mixer and dry mix at 150 rpm for 5 minutes until evenly mixed.

[0101] (3) Mixing and modification: Mix the dry mix from step (2) and the liquid mixture from step (1). First, stir at 600 rpm for 1.5 minutes, then stir at 300 rpm for 2 minutes to form a uniform concrete paste. Finally, add pure acrylic emulsion and styrene-acrylic emulsion, and stir at 400 rpm for 4 minutes to obtain the final product.

[0102] Test case The concrete samples from the examples and comparative examples were subjected to performance tests. Slump, spread, setting time, compressive strength, flexural strength, flexural-compression ratio, and impermeability were all tested according to the methods specified in DL / T 5117-2021 "Test Procedure for Underwater Non-Dispersible Concrete".

[0103] The dynamic water retention rate was determined using the dynamic water flushing test method: Freshly mixed concrete was placed in a cylindrical mold and allowed to stand for 2 hours before being demolded, and its initial mass was measured. The concrete was then placed in a dynamic water flushing device and tested under conditions of 0.5 m / s for 1 hour and 1.0 m / s for 30 minutes, respectively. After flushing, the surface moisture was removed, and the mass was measured. The dynamic water retention rate was calculated as the ratio of the retained mass to the initial mass. The arithmetic mean of three parallel specimens was taken.

[0104] The results are shown in Tables 1 and 2.

[0105] Table 1. Workability and impermeability data of concrete

[0106] Table 2. Data on the mechanical properties, toughness, and water dispersion resistance of concrete.

[0107] As can be seen from Tables 1 and 2, all embodiments exhibit an excellent balance of overall performance: good workability, short initial setting time, high impermeability, good early and late strength, high toughness, and good resistance to water dispersion.

[0108] Comparative Example 1 data shows that the absence of sulfoaluminate cement leads to a significantly prolonged initial setting time, decreased impermeability, slow early strength development, reduced later strength, and decreased resistance to water erosion, resulting in deteriorated underwater performance. Comparative Example 2 data shows that the absence of the composite alkali activator prevents the full utilization of the activity of a large amount of solid waste admixtures, significantly impairing the early and later mechanical properties and impermeability of the material, while also negatively impacting its resistance to water dispersibility. Comparative Examples 3, 5, 6, and 7-9 illustrate the significant impact of the anti-water dispersant formulation and its specific preparation process on the performance of concrete, especially its resistance to water dispersibility. Comparative Example 4 data shows that the lack of a toughening system composed of polypropylene fiber, basalt fiber, pure acrylic emulsion, and styrene-acrylic emulsion leads to increased material brittleness, a significant decrease in the flexural-to-compression ratio and impermeability, which is detrimental to the safety of the tunnel structure under long-term loads.

[0109] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-toughness, water-dispersible-resistant concrete for backfilling behind TBM tunnel segments, characterized in that, By weight, including: 210-270 parts of ordinary Portland cement, 80-120 parts of sulfoaluminate cement, 35-55 parts of fly ash, 20-40 parts of coal gangue powder, 30-50 parts of tailings powder, 25-35 parts of silica fume, and 60-100 parts of composite alkali activator. 360-440 parts of recycled fine aggregate from construction waste, 180-240 parts of fine aggregate from coal gangue, and 800-900 parts of slag; 6-8 parts polypropylene fiber, 5-10 parts basalt fiber, 25-45 parts pure acrylic emulsion, and 15-30 parts styrene-acrylic emulsion; 8-17 parts water-reducing agent, 6-9 parts polyethylene glycol, and 12-20 parts composite anti-water dispersibility agent; 380-420 parts water; The composite alkali activator includes water glass, sodium carbonate, and biomass straw ash, with a mass ratio of water glass, sodium carbonate, and biomass straw ash of (2.0~3.0): (1.0~2.5): (2.5~4.5); the composite anti-water dispersibility agent includes modified hydroxyethyl methyl cellulose ether, agar, and xanthan gum, with a mass ratio of modified hydroxyethyl methyl cellulose ether, agar, and xanthan gum of (1.5~3.5): 1: (0.4~1.5). The modified hydroxyethyl methyl cellulose ether is a hydroxyethyl methyl cellulose ether modified with formaldehyde. The preparation method is as follows: 100 parts by weight of hydroxyethyl methyl cellulose ether is dispersed in a mixed solvent of ethanol and water. 3-8 parts by weight of formaldehyde solution are added under stirring. The pH is adjusted to 2-4 with acid solution, and the reaction is carried out at 50-70℃ for 2-4 hours. After the reaction is completed, the mixture is neutralized with alkali, washed, dried, and pulverized to obtain the modified hydroxyethyl methyl cellulose ether. The preparation method of the high-toughness, water-dispersion-resistant concrete includes the following steps: Water glass, sodium carbonate, biomass straw ash and some water are premixed and stirred to form a composite alkali activator slurry; The composite anti-water dispersant was mixed with some water, heated to dissolve, and then cooled to obtain a gel-like precursor. The gel-like precursor, polyethylene glycol, water-reducing agent and remaining water are stirred and mixed, and then the composite alkali activator slurry is added and stirred to obtain a mixture. A dry mix is ​​prepared by mixing ordinary silicate cement, sulfoaluminate cement, fly ash, coal gangue powder, tailings powder, silica fume, recycled fine aggregate from construction waste, fine aggregate from coal gangue, slag, polypropylene fiber, and basalt fiber. The dry mix and the liquid mixture are stirred to obtain a concrete paste. Then, pure acrylic emulsion and styrene-acrylic emulsion are added and stirred evenly to obtain the high-toughness water-dispersible concrete.

2. The high-toughness, water-dispersion-resistant concrete as described in claim 1, characterized in that, The modulus of the water glass is 2.0 to 2.

8.

3. The high-toughness, water-dispersion-resistant concrete as described in claim 1, characterized in that, The polyethylene glycol has a molecular weight of 400-1000; the water-reducing agent includes ether-based polycarboxylate water-reducing agent and aliphatic water-reducing agent; the mass ratio of the ether-based polycarboxylate water-reducing agent to the aliphatic water-reducing agent is (1.0-2.0):

1.

4. The high-toughness, water-dispersion-resistant concrete as described in claim 1, characterized in that, The polypropylene fibers have an average length of 10-20 mm and a diameter of 30-50 μm; the basalt fibers have an average length of 12-18 mm and a diameter of 13-15 μm.

5. The high-toughness, water-dispersion-resistant concrete as described in claim 1, characterized in that, The pure acrylic emulsion has a solid content of 45-55 wt%; the styrene-acrylic emulsion has a solid content of 45-55 wt%.

6. The high-toughness, water-dispersion-resistant concrete as described in claim 1, characterized in that, The particle size of the recycled construction waste fine aggregate and the coal gangue fine aggregate is no greater than 5 mm; the particle size of the slag is 5-15 mm; and the bulk density of the slag is 900-1100 kg / m³. 3 Water absorption rate ≤5wt%.

7. The high-toughness, water-dispersion-resistant concrete as described in claim 1, characterized in that, The strength grade of the ordinary silicate cement is not lower than 42.5; the strength grade of the sulfoaluminate cement is not lower than 42.

5.

8. The method for preparing high-toughness, water-dispersion-resistant concrete according to any one of claims 1 to 7, characterized in that, Includes the following steps: Water glass, sodium carbonate, biomass straw ash and some water are premixed and stirred to form a composite alkali activator slurry; The composite anti-water dispersant was mixed with some water, heated to dissolve, and then cooled to obtain a gel-like precursor. The gel-like precursor, polyethylene glycol, water-reducing agent and remaining water are stirred and mixed, and then the composite alkali activator slurry is added and stirred to obtain a mixture. A dry mix is ​​prepared by mixing ordinary silicate cement, sulfoaluminate cement, fly ash, coal gangue powder, tailings powder, silica fume, recycled fine aggregate from construction waste, fine aggregate from coal gangue, slag, polypropylene fiber, and basalt fiber. The dry mix and the liquid mixture are stirred to obtain a concrete paste. Then, pure acrylic emulsion and styrene-acrylic emulsion are added and stirred evenly to obtain the high-toughness water-dispersible concrete.

9. The application of the high-toughness water-dispersible concrete as described in any one of claims 1 to 7 or the high-toughness water-dispersible concrete prepared by the preparation method described in claim 8 in the construction of void filling behind the tunnel segment wall in TBM tunnel engineering.

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